Known sliding blocks are rectangular and in particular square, the perpendicular spacing of the side walls or surfaces of the sliding block, in the case of a rectangular cross-section the smaller groove base width dimension, corresponds to the groove in a grooved rail. It is consequently necessary to mount the sliding block in a groove from the end face of the grooved rail, which requires considerable time and effort.
The problem of the invention is consequently to so further develop a clamping element and a device of the aforementioned types, that a simple possibility is provided for inserting the sliding block in an undercut groove with secure and reliable fixing possibilities.